The above patent approaches may work technically, but visible light is annoying and infrared or ultraviolet light impinging upon the eye is not desirable to many users because of perceived eye damage which may accumulate from long exposure. Successful commercialization of a device requires that the buyer feel safe in its use.
Some of the referenced approaches focus beams directly into the eye, and others have beams in close proximity such that scattered or misdirected light may enter the eye. Most beams are of low power level and would not be expected to damage the eye, but this would be very hard to prove. The present invention alleviates this problem by utilizing the eyelash, which is a safe distance from the eye, and by carefully focusing the light beam so that it does not enter the eye. Only the eyelash can scatter the light beam, and in that instance the eye is closed and the alarm activated. Companies are more comfortable in commercializing a product which has no chance of attracting liability lawsuits.
Much camera based sleep prevention work is ongoing, an example of which is U.S. Pat. No. 5,689,241 Nov. 1997 Clarke, Sr., et al., and these devices have the advantage of multi-user use, but have the difficulty of rapid complex image acquisition and processing which will likely require a high price. Cameras may be passive during the day but may require eye illumination at night. In addition, there may be a signal attenuation if the driver is wearing sun glasses. Automobile camera installations may be expected in a few years on some expensive vehicles, but it will be slow and costly in spreading to all new vehicles. New car installations will not affect the millions of vehicles already on the road. In addition, cameras fixed to a vehicle are of a single use, whereas, this invention may be used by watchmen and others who must move about on foot from place to place.
Falling asleep in the wrong situation can be a life or death matter, and many injuries and deaths now attributable to drunken driving and other causes may be due to falling asleep at the wheel. Drowsy driving has been a key focus for a number of inventions over the past 25 years. Among these are rumble strips, ear mounted head nodding sensors, steering wheel motion sensors, eyelid and eyelash sensors, eye muscle sensors, brain wave sensors, and face scanning cameras. Each of these has particular advantages and disadvantages. The eyelash sensor, invented some twenty years ago, is one of the better choices for commercialization because it is moderate in price and complexity, is expected to be reliable in operation, and is predictive of sleep.
This present invention, referred to herein as xe2x80x9cDrowsy alarm glassesxe2x80x9d, is an improvement of the original run-out U.S. Pat. No. 4,144,531, March of 1979, by Henricus Anbergen. The improvements consist of the following: the use of a focused beam for accurate eyelash detection, the elimination of the light attenuation and scattering from the mirrors and reflux cell, the addition of a filter to minimize ambient light effects, the addition of a shield to block direct sunlight, the simplification of the optical path to improve peripheral vision, the ability to fold, and the ability to be removed from the users eyeglasses when not needed.
A safety apparatus which utilizes an eyeglass mounted light emitter and detector and which will sound an alarm when a drowsy driver""s eye closes and his eyelashes interrupt a light beam. This device will prevent drivers from falling asleep and thereby prevent accidents.
This device is an improvement of run-out U.S. Pat. No. 4,144,531 May 1979 by Henricus Anbergen because it provides a method of focusing the light beam to a small diameter at the center of the eyelash where the eyelash is more easily and reliably sensed. In addition, the focused beam does not have stray light rays which may enter the eye. Usage of the device by pilots, factory workers, guards, and watchmen will improve their work performance and safety.